Brazil suspects leprosy spreads through armadillos

[SÃO PAULO] Hunting and eating armadillos can mean a greater risk of getting sick with leprosy, an infectious disease that affects the nervous system.

This is the conclusion of an international group of researchers who evaluated 16 armadillos captured in two villages of the municipality of Belterra, in the state of Pará, in Brazil’s Amazon region.

The site was chosen for its high density of these mammals in the surrounding forests, and for the high percentage of people who hunt or eat armadillo.

Although these activities are prohibited in Brazil, they remain common in parts of the country where these animals abound and other sources of protein are scarce.

The researchers analysed samples from the liver and spleen of armadillos captured by villagers. They found the DNA of the bacterium Mycobacterium leprae, which causes leprosy, in 62 per cent of the animals.

 Through tests on blood taken from 146 local residents, the scientists confirmed leprosy in seven of the villagers. A further 91 people had antibodies against the pathogen, suggesting that they had already been in contact with the microorganism.

“Although treatment is free, one of the difficulties is the diagnosis of the disease,”

Ricardo Arcêncio

Those who reported consuming the animal's flesh frequently — more than once a month or twice a week — had more antibodies in their blood.

"The results present evidence that reinforces the suspicion that the armadillos could have [transmitted] and transmit the leprosy bacteria, acting as a reservoir of the pathogen," said Marcus Vinicius Rodrigues, a biomedical researcher at the Universidade do Oeste Paulista, who did not participate in the study, in an interview with SciDev.Net.

That signals a problem, he added, because some 65 per cent of people in that region consume armadillo meat at least once a year — and as these are large animals, a hunter who catches one often shares it with family and friends.

"But to establish a cause and effect connection, it would be necessary to demonstrate that the bacteria identified in armadillos [are of] the same strain found in people's blood," explains John Spencer, an immunologist at Colorado State University in the United States.

Spencer is a lead author of the study, published in the journal PLoS Neglected Tropical Diseases.

Leprosy leads to muscular weakness and generates white or reddish spots on the skin. It is often transmitted through contact with the nasal secretions of infected people, or through coughs and sneezes. It is caused by the bacterium M. leprae, which was identified by the Norwegian doctor Gerhard Hansen in 1873.

Today treatment is simple, free and efficient — based on the chemical compound sulfone and two other drugs, rifampin and clofazimine.

However, Brazil has the second largest number of cases in the world, after India. In 2016, the country’s Ministry of Health registered 25,218 new cases.

"Although treatment is free, one of the difficulties is the diagnosis of the disease," says Ricardo Arcêncio, professor at the School of Nursing of the University of São Paulo, in an interview with SciDev.Net. He explains that people may avoid seeking care because of stigma in relation to leprosy.

"Another factor is the socioeconomic conditions that contribute to the chain of transmission of the disease, such as low family income, precarious housing and too many people per household," adds Arcêncio, who did not participate in the study.

Spencer says it is unlikely that people who live in the region will change their eating habits — even if they know that armadillos transmit diseases.

"Eating armadillos is part of the social and cultural lifestyle of these people, and this will continue for generations," he explains.

Biologist Selma Jeronimo, from the Institute of Tropical Medicine of the Federal University of Rio Grande do Norte, points out that the study’s findings suggest these animals should be taken into account in the formulation of public policies to control the disease.

"The elimination of leprosy, as well as all other neglected diseases, is a complicated goal because it involves political issues and efforts, investments in research and interest in diseases that affect poor and vulnerable populations," Rodrigues points out.

This article was produced by SciDev.Net’s Latin America and the Caribbean edition.